Individual piglets' contribution to the development of tail biting.

Conflicting hypotheses exist about the contribution of individual pigs to the development of a tail-biting outbreak, but there is limited quantitative information to support or dismiss them. This study aims to quantify the development of tail-biting behaviour at pen and individual piglet level, before and after the first visible tail damage. Video recordings of 14 pens with tail-biting outbreaks and individually marked weaned piglets were used to observe tail-biting incidents (TBIs; piglet biting a penmate's tail). When visible tail damage was first observed in a pen (i.e. day of tail biting outbreak; D0), the video recordings of the previous 6 (till D-6) and the following 6 days (till D6) were analysed every other day for TBIs and the identities of the biter and bitten piglet were recorded. The average TBIs per individual piglet (within each pen) per observation day were analysed to quantify the development of tail-biting behaviour and to identify pronounced biters and/or bitten piglets. The (absence of) coherence for TBIs in a pen was used to test whether biters preferred a specific penmate. There was an exponential increase in the intensity (linear on log scale) of the TBIs from an average of 0.7 bites/h at D-6 to 2.3 bites/h at D6. An additional negative quadratic component suggests that a plateau for tail-biting behaviour was reached by the end of the observation period. Before any visible tail damage was observed (i.e. before D0), 82% of the piglets performed and 96% of them received tail bites. After D0, the figures were 99% and 100%, respectively. One or a few pronounced biters could be identified in almost all pens. These biters already showed more tail biting at D-6 than their penmates. Furthermore, these biters showed a greater increase in tail-biting behaviour during the observation period than the average scores of their penmates. In contrast, there was no apparent increase in the receipt of bites among the piglets that had already been bitten more than their penmates at D-6. Finally, there was no significant coherence between biters and bitten piglets, indicating that biters showed no preference for biting particular penmates, even when some of them had a damaged tail. These results show that, by using observations of TBIs, possible biters or bitten piglets can already be identified 6 days before tail damage is first apparent in a pen.

Characteristics of biter and victim piglets apparent before a tail-biting outbreak.

Little is known about the characteristics of biters and victims before the appearance of a tail-biting outbreak in groups of pigs. This study aimed to characterise biters and victims (according to gender and performance) and to quantify their behavioural development during the 6 days preceding the tail-biting outbreak. The hypotheses tested were: (a) biters are more often female, are the lighter pigs in the group, are more restless and perform more aggressive behaviour; and (b) victims are more often male, heavier and less active. Using video recordings we carried out a detailed study of 14 pens with a tail-biting outbreak among the weaned piglets. All piglets were individually marked and we observed the behaviour of biters, victims and control piglets (piglet types). In every pen, each piglet type was observed every other day from 6 days before (D-6) to the day of the first visible tail damage (i.e. day of tail biting outbreak; D0). While the number of male biters (6 of the 14 biters) and male victims (11 of the 14 victims) was not significantly different (P = 0.13), this numerical contrast was considerable. The start weight of victims was significantly (P = 0.03) higher (8.6 kg) than those of biters (7.5 kg) and control piglets (8.0 kg). Biters tended (P = 0.08) to spend longer sitting/kneeling (3.1 min/h) than controls (1.7 min/h), but no differences were seen in the time spent lying or standing. Victims tended (P = 0.07) to change posture more often (restlessness) than controls and chased penmates more (P = 0.04) than biters. Victims also performed more (P = 0.04) aggressive behaviour than biters and controls. In contrast, biters tended (P = 0.08) to be chased by penmates more often and tended (P = 0.06) to receive more aggressive behaviour than controls. Furthermore, biters spent longer manipulating the enrichment device (P = 0.01) and the posterior/tail (P = 0.02) of their penmates than controls and tended (P = 0.06) to perform more tail bites than victims. Victims received more posterior/tail manipulation (P = 0.02) and tail bites (P = 0.04) than controls. It was also noticed that, independent of piglet type, restlessness (P = 0.03) increased and the frequency of performed tail bites tended (P = 0.08) to increase in the 6 days preceding a tail-biting outbreak. These findings may contribute to the early identification of biters or victims and support the development of strategies to minimise the occurrence of tail biting.

Comparison of three different diets for organic broilers: effects on performance and body condition.

1. The aim of this study was to assess the feasibility of 100% organic feed for organic broilers by comparing it with 80% organic feed (situation at the time of the experiment; 2004) and 95% organic feed (alternative). 2. Diets were optimised for nutritional value, allowing a maximum 10% increase in feed price when using 100% organic feedstuffs. This could only be achieved at the expense of the methionine content. 3. The birds were reared from 0 to 3 weeks of age in a broiler house in three groups of 500 broilers each on either an 80, a 95 or a 100% organic starter diet. At 3 weeks of age, they were transferred to 15 pens with an outdoor run. Each treatment group of 500 birds was divided into 5 groups of 95 and given an 80, a 95 or a 100% organic finisher diet. 4. Broilers receiving 100% organic feed reached a lower body weight and grew more slowly than those receiving 95% organic feed, mainly because of a lower feed intake. 5. Broilers on 95 or 100% organic feed had a higher incidence of breast blisters than broilers receiving 80% organic feed. 6. The cost price for meat from broilers that received 80% organic feed was euro1.83 per kg live weight. The cost prices for broilers that received 95 and 100% organic feed were euro1.84 (+0.8%) and euro1.93 (+5.4%) per kg live weight, respectively. 7. In conclusion, 95% organic feed led to a better performance than 100% organic feed in this study. Probably, the lower methionine content in the 100% organic feed negatively affected performance. The results for 95% organic feed were similar to 80% organic feed, except for a higher incidence of breast blisters.

Performance and individual feed intake characteristics of group-housed sows fed a nonstarch polysaccharides diet ad libitum during gestation over three parities.

The objective of this experiment was to study the effects of feeding group-housed gestating sows a diet with a high level of fermentable nonstarch polysaccharides (NSP; approximately 45% sugar beet pulp as fed) ad libitum on the development in individual feed intake characteristics and reproductive performance during three successive reproduction cycles. Performance of the ad libitum-fed sows was compared to the performance of sows that were fed a conventional diet restrictedly. Feed intake characteristics during gestation were only measured in the ad libitum-fed sows. One hundred and nineteen sows were assigned to one of two gestation feeding regimens. Gestating sows were fed a conventional Dutch diet restrictedly or a diet with a high level of fermentable NSP ad libitum. During lactation, sows were given free access to a commercial lactation diet from d 6 after parturition onward. The ad libitum-fed sows ate 1.3 kg/d more during gestation than the restrictedly fed sows (P < 0.001), resulting in higher body weight and backfat gains during gestation (P < 0.05). Sows that were fed ad libitum during gestation lost more body weight and backfat during lactation (P < 0.001) than sows that were fed restrictedly during gestation. Feed intake during lactation, however, did not differ between sows that were fed restrictedly or ad libitum during gestation. The numbers of total piglets born, live-born and stillborn piglets, piglet birth weight, weaning-to-estrus interval, and percentage of sows that returned to estrus after first insemination were not affected by gestation feeding regimen. Mean daily voluntary feed intake (as-fed basis) over the three reproduction cycles in the ad libitum-fed gestating sows was 4.2 kg/d. Depending on the number of preceding reproduction cycles during which a sow was fed ad libitum, the maximum voluntary feed intake was reached in Parity 3, 4, or 5 and then remained stable in subsequent parities. Mean daily feed intake of the ad libitum-fed sows increased from wk 2 to 6 of gestation and then decreased to wk 15 of gestation. The mean number of daily visits with feed intake over the three reproduction cycles was 13.8. On average, ad libitum-fed sows spent 90 min/d on eating. This study shows that it is possible to feed gestating sows a diet with a high level of fermentable NSP ad libitum during three successive reproduction cycles without negative effects on reproductive performance.

Performance of sows fed high levels of nonstarch polysaccharides during gestation and lactation over three parities.

The effect of feeding sows a starch diet or a diet with a high level of nonstarch polysaccharides (NSP) during gestation, lactation, or both gestation and lactation during the first three parities on reproductive performance, body weight, and backfat was studied. Four-hundred and forty-four postpuberal gilts were allotted to a 2 x 2 x 2 factorial experiment. Treatments were diet composition during gestation (including the weaning-to-estrus interval; G-Starch: 274 g/kg of starch and 123 g/kg of fermentable NSP or G-NSP: 86 g/kg of starch and 300 g/kg of fermentable NSP), diet composition during lactation (L-Starch: 293 g/kg of starch and 113 g/kg of fermentable NSP or L-NSP: 189 g/kg of starch and 216 g/kg of fermentable NSP) and group-housing system during gestation (free access stalls or electronic feeding). Both gestation diets were formulated to be isoenergetic. During lactation, sows were given free access to the lactation diets from d 6 after parturition onwards. Body weight and backfat gains during gestation were lower in sows fed the G-NSP diet than in those fed the G-starch diet (P < 0.001). The effects were more pronounced in the electronic feeding system than in the free access stalls. These results indicate an overestimation of the energy value of fermentable NSP. Body weight and backfat losses during lactation were less in sows fed the G-NSP diet during gestation than in those fed the G-starch diet (P < 0.05),which can be explained by a 0.4 kg/d higher (P < 0.001) feed intake during lactation of the sows fed the G-NSP diet. Sows fed the L-NSP diet lost more backfat during lactation than sows fed the L-starch diet (P < 0.05). The number of total piglets born and live-born piglets was 0.5 piglet higher in sows fed the G-NSP diet than in those fed the G-starch diet (P < 0.05). Lactation diet did not affect the number of total piglets born or live-born piglets. This study shows that, although high NSP diets negatively influence body weight and backfat thickness of the sows, it is possible to feed sows a diet with a high level of fermentable NSP diet during both gestation and lactation without negative effects on reproductive performance. Under the conditions of this study, feeding sows a diet with a high level of fermentable NSP during gestation and a high level of starch during lactation seems the most favorable feeding strategy.